From W3C Wiki
This is a recently introduced solution based upon Bluetooth Low Energy (BLE) which has a range of up to 50 metres. Stores and restaurants can greet customers by name as they walk in. The customer needs to have a phone with BLE hardware and to have installed the PayPal app along with having set up a PayPal account, and registered a photo of themselves. The store needs a BLE dongle provided by PayPal. This radiates a beacon signal that phones detect and respond with the user's identity. Customers are prompted on their phone if they would like to "check in" to the store/restaurant, and are offered an "always allow" auto checkin for subsequent occasions. A store could have a notebook computer with the dongle at the podium used for greeting customers at the entrance. The computer shows the customer's name and photo, along with information on the customer's preferences. Beacon allows stores/restaurants to offer customers personalized deals. However, customers are not tracked as they move about the store. One concern that needs addressing is the potential for third parties to abuse BLE to track people without their knowledge.
What is currently unclear is the check-out process. In a restaurant, customers could pull out their phone to review the check/bill and confirm the payment. This works because the waiter is given your identity when you are seated and books items to that identity. For stores it is more complicated. A manual check-out process is still needed, where the items to be purchased are scanned. Customers needs to identify themselves to the point of sales terminal. Can BLE be limited to very short range communications analogous to NFC? If so then, the terminal could readily identify the customer nearby to the BLE device attached to the terminal. Other possibilities include the sales assistant identifying customers from their photos (a potentially hard problem in large stores with many customers present at the same time), or even via scanning a barcode presented on the customer's phone by the app.
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